An application of machine type communications (MTC) or Internet of Things (IoT) is to report small data for non-urgent cases. For example water, electric, or gas meters at home may send data to the cloud network in order to deliver such data to users or utility companies. Similarly, temperature or rainfall sensors deployed on mountains may transmit observation data to research institutes or the government. The characteristics pertain to this type of application include small data, device-originated report, non-urgent, and low power consumption. Small data means that a total amount of a transmission could only be a few packets. Non-urgent means that the data does not have to arrive at a destination instantly but is delay tolerant such that in most cases it would not make any difference if the data arrives at a destination 20-30 minutes after it is transmitted.
The current process of transmitting a small data is shown in FIG. 1˜FIG. 4 and described by their corresponding written descriptions. A communication system such as the long term evolution (LTE) communication system is a packet-switch system. Under such a system, a user equipment (UE) would require an internet protocol (IP) address to order to access the Internet. In the LTE system, a user equipment may obtain an IP address by performing an Attach procedure.
A typical attachment procedure could be found in 3GPP technical specification 24.301. A relevant section of 5.5.1.2.4 of 3GPP technical specification 24.301 quotes in part “. . . If the attach request is accepted by the network, MME shall send an ATTACH ACCEPT message to the UE and starting timer T3450. The MME shall send the ATTACH ACCEPT message together with an ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message contained in the ESM message container information element to activate the default bearer.
A relevant section of 6.4.1.2 of 3GPP technical specification 24.301 quotes in part “The MME shall initiate the default bearer context activation procedure by sending an ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message and enter the state BEARER CONTEXT ACTIVE PENDING. When the default bearer is activated as a part of the attach procedure, the MME shall send the ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message together with ATTACH ACCEPT and shall not start the timer 3485 . . . .”
FIG. 1 illustrates the content of an Activate Default EPS Bearer Context Request message in accordance with Table 8.3.6.1 of the 3GPP technical specification 24.301. It can be seen from FIG. 1 that the PDN address is an information element of the ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message. This means that an IP address can be obtained by a UE during an Attach procedure to a LTE network.
For a LTE network, after a UE has attached to the network, the UE would go to RRC_IDLE mode if the UE has no data to transmit or to receive. After being in RRC_IDLE mode, the UE would need to initiate a Service Request procedure if the UE wants to start transmitting or receiving data once again. FIG. 2 illustrates a signaling diagram of a UE trigger service request procedure in accordance with 3GPP technical specification 24.301. According to FIG. 2 as well as section 5.3.4.1 of the 3GPP technical specification 24.301, if a MTC device such as a home electric or gas or water meter wants to transmit data to a utility company, the MTC device would need to trigger a Service Request procedure by transmitting a Service Request message as shown in step 1 of FIG. 2 in order to transmit the data.
Subsequently, in response to receiving the Service Request, in step 2 an Evolved Node B (eNB) would forward the Service Request to a Mobility Management Entity (MME). In step 3, an Authentication/Security procedure would be performed to authenticate the MTC device. After the MTC device has been authenticated, in step 4, the MME would transmit a S1-AP Initial Context Setup Request message. It is important to note that within the S1-AP Initial Context Setup Request message, the MME would transmit a set of quality of service (QoS) parameters which is selected by the MME along with address of the Serving Gateway (S-GW) as well as a S1 tunnel ID (S1-TEID). In step 5, in response to receiving the S1-AP Initial Context Setup Request message, the eNB would establish a radio bearer with the MTC device. After the radio bearer has been established, in step 6, the MTC device would be able to transmit small data to the eNB which would then forward the small data to the S-GW which would then forward the small data to the packet data network gateway (PDN GW).
In step 7, the eNB would transmit a S1-AP Initial Context Setup Complete message to the MME after procedures associated with step 4 are completed. In step 8, the MME would transmit a Modify Bearer Request message to the S-GW. In step 9, the S-GW may forward the Modify Bearer Request message to the PDN GW. In step 10, the PDN GW would coordinate with a Police and Charging Rules Function (PCRF) to initiate an IP-CAN Session Modification. In step 11, the S-GW may receive a Modify Bearer Response from the PDN GW. In step 12, the Service Request procedure would be completed when the MME receives a Modify Bearer Response message from the S-GW.
To describe step 4 of FIG. 2 with further detail, FIG. 3 illustrates the content of an Initial Context Setup Request message in accordance with 3GPP technical specification 36.413. The Initial Context Setup Request message is sent by a MME to an eNB. A relevant section of 9.1.4.1 of the 3GPP technical specification 36.413 quotes in part “The MME sends S1-AP initial Context Setup Request (Serving GW address, S1-TEID(s) (UL), EPS bearer QoS(s), Security Context, MME Signaling Connection ID, Handover Restriction List, CSG Membership Indication) message to the eNB . . .” It can be seen from FIG. 3 and its corresponding description that the Bearer QoS, the S-GW address, and T1-TEID are contained in the information elements of an Initial Context Request message. Therefore, the Bearer Qos is required by the eNB to allocate radio resource to a MTC UE. The S-GW address and Ti-TEID(s) are used by the eNB to connect to the S-GW so that the eNB would be able to forward small data from a MTC device to a S-GW.
FIG. 4 shows that the E-RAB Level QoS parameters 401 is a part of the information elements which defines the QoS to be applied to an E-RAB as described by section 9.2.1.15 of 3GPP technical specification 36.413. For this disclosure, the 3GPP technical specification 24.301 and 3GPP technical specification 36.413 are incorporated by reference in the way that the definition of the terms used in this disclosure are consistent with definition of the terms used in these technical specifications.